Hepatocellular carcinoma (HCC) is an aggressive malignancy that has a survival rate of 14% [1]. HCC is the fifth most common cancer in the world, and is the third leading cause of cancer mortality, responsible for between 250,000 and 800,000 deaths per year. Most HCC patients are diagnosed at a late stage using conventional methods of detection, with a survival rate less than 5% after the diagnosis and subsequent treatment. The prognosis is much better if HCC patients are diagnosed at an early stage and treated with surgical and chemotherapeutic intervention. Unfortunately, the early stage of liver cancer is mostly asymptomatic, making the early detection of liver cancer a challenge.
Current methods in detecting HCC include monitoring high risk groups—such as those infected with HBV or HCV—with regular (usually annual or biannual) physical examinations, serum liver function tests (LFTs), ultrasound and other imaging studies. These methods all have their shortcomings. For example, ultrasound imaging is not sensitive for detecting small liver lesions. Other imaging methods, such as CT scan and MRI scan, are very expensive and submit patients to radiation exposure, prohibiting routine use of such methods.
In addition to imaging techniques, elevated serum concentrations of alpha-fetoprotein (AFP) is a useful surrogate marker for HCC, because at least 60% of HCC patients have elevated AFP level at the time of diagnosis. However, elevated level of AFP is influenced by and can result from a number of non-malignant conditions. It is nearly impossible to detect HCC sufficiently early using current methods. Thus, there is a clear and urgent need for non-invasive, sensitive, reliable methods for the early detection of HCC.